<!DOCTYPE html>
<html lang="en">

<head>
	<meta charset="UTF-8">
	<meta http-equiv="X-UA-Compatible" content="IE=edge">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<title>Document</title>
	<style>
		.box1 {
			width: 100px;
			height: 100px;
			float: left;
			border: 1px solid #000;
		}

		.box2 {
			width: 100px;
			height: 100px;
			float: left;
			border: 1px solid #000;
		}

		.box {
			background: yellow;
			overflow: hidden;
		}
	</style>
</head>

<body>
	<div class="box">
		<div class="box1"></div>
		<div class="box2"></div>
	</div>
</body>

</html>